Radial flow steam turbine

ABSTRACT

Provided is a high-efficiency, realistic, radial flow steam turbine such that the steam supply method is simplified, and that a sufficient amount of steam is supplied to the interior of a turbine unit which is additionally provided in the axial direction. The radial flow steam turbine is equipped with a rotation shaft; a rotor disk connected to the rotation shaft; rotor blades are mounted on the rotor disk; stator disks which face the rotor disk are supported by a casing by being fixed thereto; stator blades are mounted on the stator disk; and an operating steam circulation path is formed wherein the rotor blades on the rotor disk and the stator blades on the stator disk are alternately disposed in the radial direction, and wherein the flow direction of operating steam is in a radial direction which is outward with respect to the rotation shaft. Also, the radial flow steam turbine is configured in such a way that the steam supplied by a steam supply source is circulated as operating steam in the operating steam path, and that thereby the rotor disk and the rotation shaft are rotated. In this radial flow steam turbine, openings are provided in those areas of the rotor disk in the vicinity of the rotation shaft, with the result that an axial steam supply passage is secured.

TECHNICAL FIELD

This invention relates to a steam turbine, and particularly relates to aradial flow steam turbine in which the operating steam travels in anoutflow direction, that is the radial direction perpendicular to therotation shaft.

BACKGROUND ART

A steam turbine operated by the dilatational energy of the expandingsteam is commonly used for supplying electric power all over the world.For enhancing the turbine efficiency, the operation steam temperatureand the operating steam pressure become higher and the scale of theplant becomes larger. In some cases, the steam turbine is combined witha gas turbine for achieving the combined steam circle. On the otherhand, the recycling of the wasted heat is required for reducing thecarbon-dioxide. Examples of the wasted heat are the wasted heat from thediesel engine in ships, the wasted heat from the process operation infactories, and the wasted heat from garbage disposal facilities. It isdesired to convert those wasted heat energy into available electricenergy. However, it is not achieved simply by scaling down the largescale steam turbine such as for the power plant, since the efficiencywill be deteriorated. Therefore the appropriate small scale steamturbine is required corresponding to the demand for small scaleelectricity generation.

The prior steam turbine in general converts the dilatational energy ofthe expanding steam into the rotary motion by utilizing the pressuredifference along to the rotation shaft by supplying the steam so as tokeep the steam pressure at the turbine input terminal high and the steampressure at the turbine output terminal low. For this reason, the axialflow turbine in which the direction of the steam flow is parallel to therotation shaft has been developed and has been up-scaled correspondingto the demand for large scale power plants. Besides the axial flowturbine, the radial flow turbine utilizing the steam pressure differencealong the radial direction perpendicular to the rotation shaft, in otherwords, the outflow direction, is known in the prior art. The radial flowsteam turbine is suitable for the small scale type turbine and is arelatively high efficiency turbine. However it is not suitable for thelarge scale type turbine, so it had faded away from the market use.However, it is being reconsidered once again from the necessity of thedemand for re-use of the small scale industrial wasted heat energy. Thetypical example of the radial flow steam turbine is a Ljungstrom turbine(prior art 1, 2 and 3).

The characteristic of the Ljungstrom turbine (FIG. 3 shown in the priorart 1) representing the conventional radial flow steam turbine, which isthe common base technology of the listed prior art, is that two facingrotor disks are attached respectively to the front edge of two facingrotation shafts, and the steam flow passes from the center part to theouter part in the outflow radial direction formed between these facingtwo rotor disks. The cluster of the rotor blades are mounted on eachsurface of the facing two rotor disks respectively. The rotor blades arearrayed annularly on concentric paths, each set of the rotor blades isarrayed on the surface of the facing two rotor disks respectively in theradial direction in order to rotate the one disk in the clockwisedirection and the other disk in the counterclockwise direction byutilizing the aerial bounce generated between the rotor blades attachedto the one rotor disk and the rotor blades attached to the other rotordisk (see FIG. 7 of this application)

-   Prior art 1: Tokkai 2005-105854 JP-   Prior art 2: Tokkai 2006-144758 JP-   Prior art 3: Tokkai 2005-042567 JP-   Prior art 4: U.S. Pat. No. 5,071,312-   Prior art 5: U.S. Pat. No. 7,244,095

DISCLOSURE OF THE INVENTION The Problems to be Solved

The above conventional Ljungstrom turbine as the conventional radialflow steam turbine includes the two facing rotor disks rotating in theclockwise and the counterclockwise respectively by utilizing the aerialbounce, and the two facing rotation shafts having the rotor disk at thefront edge (Prior art 1 and 2). There is another type of theconventional radial flow steam turbine that includes a stator disk onwhich a cluster of stator blades are mounted, a rotor disk on which acluster of rotor blades are mounted, and a rotation shaft on which therotor disk is fixed (Prior art 4 and 5). The basic structure of theradial flow steam turbine in these prior art 1 and 2 can employ only onerotor disk fixed to the rotation shaft. By this reason, there is alimitation on obtaining large power output.

The prior art 3 and 4, in order to solve the above-mentioned problem,includes rotor blades mounted on the both side surface of the rotordisk, the steam passages along to the radial flow direction are formedon the both side surfaces of the rotor disk, and the plural rotor disksare installed to the rotation shaft.

However, there is a problem of how to secure the steam supply to eachsteam passage formed in the radial outflow direction among plural disksin those prior art 1 to 4. In order to solve this problem, steam issupplied by the axial steam passage formed through the rotation shaft,the steam goes through the rotation shaft and bent to the steam passageformed on the both sides of rotor disks in the radial outflow directionvia small holes opened formed in the pipe wall of the rotation shaft.However, by this method, another problem occurs with the rotation shaftdue to its heat expansion because of the hot and high pressure steam.Moreover, there is a serious actual problem that the amount of thesupplied steam is limited by the small size holes, so the amount of thesupplied steam is not enough for the steam passage to be reach to theradial outflow via the small holes on the limited diameter and thelimited surface of the rotation shaft. As a result, a sufficient amountof output cannot be obtained. In addition, it is difficult tomanufacture such a turbine, and the manufacturing cost will be high, soit has not become popular in the actual industrial use.

Moreover, the amount of the surface area for steam flow through the gapbetween the rotor disk and stator disk is almost the same even if theamount of the surface area of the rotor blades is increased ordecreased. Regarding the ratio of the amount of the surface area of therotor blades and the amount of the surface area of the gap for the steamto be flowed, the amount of the surface area of the rotor blades shouldbe relatively large enough. In the prior art 3, the small rotor bladesare employed, so the steam leakage loss will be large. As a result, itis not suitable for the actual use even if the number of the rotor disksis increased.

Therefore, in order to increase the output of the radial flow steamturbine, the rotor blades and the stator blades are arrayed inmultistage manner. The steam to have been decompressed and to haveexpanded in the steam passage to the radial outflow becomes faster andgives the rotating motion energy to the rotor blades. However, the rapidexpansion of the steam occurrs, the volume of the operating steam isexpanded rapidly, it is difficult for steam to run through the gapbetween the rotor blades and the stator blades. As a result, the steamflow may be blocked and stuffed, so the speed of the steam flow may bedecreased.

It is an object of the present invention to provide a high efficiencyradial flow steam turbine by simplifying the steam supply method andsupplying a sufficient amount of steam in the multiplied turbine unitinstalled on the rotation shaft.

Means for Solving the Problems

In order to achieve the above-mentioned object, the present invention ofa radial flow steam turbine comprises; a rotation shaft; a rotor diskconnected to the rotation shaft; rotor blades mounted on the rotor disk;a stator disk facing to the rotor disk fixed and supported by a casing;stator blades mounted on the stator disk; wherein the rotor bladesmounted on the rotor disk and the stator blades mounted on the statordisk are arrayed alternately in the radial direction; an operating steamflow passage in which the operating steam flows from in the vicinity ofthe rotation shaft to the outflow radial direction, wherein a steamsupplied from the steam supply source flows to the steam flow passage asan operating steam for rotating the rotor disk and the rotation shaft;and a steam supply route along to the axial direction is formed andsecured by forming a through opening on the rotor disk in the vicinityof the rotation shaft.

According to the above-mentioned configuration, the radial flow steamturbine can improve the steam supply that was difficult in the priorart, and sufficient amount of the steam can be supplied to every turbineunit arrayed in the axial direction.

It is preferable that the set of the rotor disk and the stator disk isprovided for at least one unit. Therefore, the number of the rotor diskis at least one, the rotor blades are mounted on the both sides of eachrotor disk respectively, and the stator disks face to both sides of eachrotor disk respectively. The operating steam flow passages are formed tobe at least two, and the steam is led from the steam supply source toeach operating steam flow passage via the steam supply route.

The combination of the shape of the rotor disk and the shape of thethrough opening in the vicinity of the rotation shaft of the rotor diskare as follows.

The first combination is that the rotor disk is installed on therotation shaft directly, and the through opening of the rotor disk isthrough hole in the vicinity of the rotation shaft of the rotor disk.

The second combination is that the rotor disk is a doughnut-shape hollowcircular disk having a center hole larger than the diameter of therotation shaft, wherein the rotor disk is supported by the plural rotordisk supporters fixed to the rotation shaft, and the through opening ofthe rotor disk in the vicinity of the rotation shaft of the rotor diskis the inter-gap between the rotor disk supporters.

In those combinations, if the stator disk is fixed to the casing bysecuring the gap between stator disk edge and the rotation shaft, thegap between the stator disk edge and the rotation shaft forms a part ofthe steam supply route.

It is preferable that the rotor blades mounted on the rotor disk and thestator blades mounted on the stator disk are formed outside of the steamsupply route. Because as a part of the steam supply route, the throughopening is formed in the vicinity of the rotation shaft in the rotordisk, and the gap between the stator disk edge and the rotation shaft isformed in the vicinity of the rotation shaft. Therefore the rotor bladesand the stator blades do not cover this area and secure the throughopening.

It is preferable that the steam supply directions from the steam supplysource to the operating steam flow passage via the steam supply routeare two directions, the one is the direction from the one terminal ofthe rotation shaft, and the other is the direction from the otherterminal of the rotation shaft.

Next, if there are plural sets of the rotor disk and stator disk alongthe axial direction, it is preferable that the operating steam pressureadjusting through holes for adjusting the air pressure gap among thesteam flow passages by connecting through the operating steam flowpassages are formed appropriately on the rotor disk and the stator diskbesides the steam supply route.

According to the above-mentioned configuration, if the radial flow steamturbine employs plural sets of the rotor disk and stator disk along tothe axial direction, the air pressure difference can be adjusted amongthe steam supply routes, and the operation of the radial flow steamturbine will be stable.

Next, the stage number of the rotor blades and stator blades in theradial flow steam turbine can be adjusted. A stage of the rotor bladescomprises the rotor blades arrayed annularly on concentric paths, andthe multi-stage rotor blades comprises plural stages mounted on therotor disk along the radial direction. The stator blades are mounted onthe stator disk corresponding to the rotor blades on the rotor disk.

Effect of the Present Invention

In the conventional radial flow steam turbine in the prior art, theoutput can be increased only by the method in which the number of thestages in the multi-stage of the rotor blades is increased because thereis only one rotor disk on the rotation shaft, but this method requiresvery high skill and high cost. If the conventional radial flow steamturbine in the prior art employs the rotor blades on both sides of therotor disk and plural rotor disk are added to the rotary axial disk inorder to form the plural steam passages in the radial outflow direction,the only method for supplying the steam in the prior art is limited tothe method forming the steam passage in the rotation shaft. Therefore,the steam will be supplied through the rotating rotation shaft, and asufficient amount of steam cannot be supplied. The conventional radialflow steam turbine is not in actual use. On the contrary, the radialflow steam turbine in the present invention can employ the plural setsof the turbine units including the rotor disk and the stator diskinstalled on the rotation shaft, and the steam can be supplied to everyturbine unit via the through opening formed in the vicinity of therotation shaft. In result, a sufficient amount of the steam can besupplied to every steam passage.

The radial flow steam turbine of the present invention can add anarbitrary number of the turbine unit including the rotor disk and thestator disk onto the rotation shaft according to the steam supplyability and condition. Therefore, the radial flow steam turbine of thepresent invention can be modified according to the various needs of thefacility and the steam supply condition. According to the radial flowsteam turbine of the present invention, the wasted heat from the dieselengine in ships, and the wasted heat from garbage disposal facilitiesturn into re-useable energy by converting the wasted heat energy toelectric energy. Carbon oxides can be reduced by utilizing the wastedheat energy emitted from the various processes in the facilities asavailable electric energy with high efficiency.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a concept figure of the first radial flow steam turbine 100 inEmbodiment 1.

FIG. 2 is a concept figure showing a part of the doughnut-shape hollowcircular disk fixed to the rotation shaft connected by the plural rotordisk supporters.

FIG. 3 is a concept figure showing the steam passage by forming thethrough hole as a through opening onto the rotor disk.

FIG. 4 is a concept figure showing the radial flow steam turbine whereinthe unit addition of the turbine unit including the rotor disk and thestator disk along to the rotation shaft.

FIG. 5 is a concept figure showing the radial flow steam turbineemploying a single stage of the rotor blades and stator blades.

FIG. 6 is a concept figure of the radial flow steam turbine wherein thesteam is supplied from single side direction.

FIG. 7 is a concept figure showing the conventional Ljungstrom turbineemploying the different rotating direction of the rotor blades.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

Some embodiments of a radial flow steam turbine according to the presentinvention are described below with reference to the relevant drawing.Needless to add, the claims of the present invention include but are notlimited to the embodiments. In each figure, the same number is used forthe same component, and the same explanation is omitted appropriately.The drawing is always displaying minute details in a reduced scale, andsometimes features are emphasized to help to understand this inventioneasily.

Embodiment 1

The first radial flow steam turbine 100 in embodiment 1 according to thepresent invention is described.

FIG. 1 is a concept figure of the first radial flow steam turbine 100 inEmbodiment 1. FIG. 1 is a drawing displaying the inside configurationfrom the side view.

As shown in FIG. 1, the first radial flow steam turbine 100 comprises arotation shaft 10, a rotor disk 20, a stator disk 30 and a casing 40 asbasic parts. FIG. 1 only shows the basic parts, so other parts such asperipheral parts and pipes are omitted here in order to explain simplyand focus on the operation principle.

The rotation shaft 10 is supported for free rotation by a bearing notshown in the figure. The material of rotation shaft 10 is not especiallylimited, but for example it is a stiff-high strength material in orderto secure its stiffness for tolerating dangerous rotation speed higherthan the maximum speed of rotations in the operation range for theradial flow steam turbine. There is no danger that the rotor bladescrash into each other by adopting a stiff enough axis in order tosuppress the occurrence of the resonance oscillation.

The rotor disk 20 is connected to the rotation shaft 10, and it rotatesby the force which is given to the rotor blade 21 by the operating steamflowing from the center portion to the outside in the radial directionas shown below. The rotor disk 20 rotates together with the rotationshaft 10.

The rotor blade 21 is mounted in the rotor disk 20. The rotor blade 21may be an impulse blade type or a reaction blade type. Hybridcomposition may be possible. For example, the blade mounted on theperipheral part may be the impulse blade type and the blade mounted onthe inner part the reaction blade type. For example, the rotationalspeed of the inner part is slow, and the steam pressed by the statorblade 31 can hit the rotor blade 21, so it is preferable that theimpulse blade type be adopted to this portion. On the other hand, therotational speed of the peripheral part is fast, and the steam pressedby the stator blade 31 cannot hit the rotor blade 21 sufficiently, so itis preferable that the reaction blade type be adopted to this portion.Regarding the steam flow width, the more the steam flows to the outerportion, the narrower the width becomes. Therefore, the more the steamflows to the outer portion, the lower the pressure of the steam becomesand the faster the speed of the steam becomes. In this condition, therotation force is generated on the rotor blades by converting the heatenergy into the rotation energy. The rotor blades 21 can be mounted oneither one surface or both surfaces of the rotor disk 20. For improvingthe output efficiency, the rotor blades 21 are mounted onto bothsurfaces of the rotor disk 20 in this Embodiment.

In the radial flow steam turbine 100, the number of blades 21 is notlimited. In this configuration, one stage of the rotor blades comprisesplural rotor blades arrayed annularly on concentric paths, and themulti-stage rotor blades comprises plural stages mounted on the rotordisk arrayed annularly on concentric paths. The configuration shown inFIG. 1 uses the four stages of the multi-stage rotor blades. Theinstallation position of the rotor blades 21 on the rotor disk 20 are onthe outer part of the through opening 22 because the through opening 22exists in the vicinity of the rotation shaft. The example configurationusing a single stage rotor blade 21 is described in Embodiment 2 lateron.

The through opening 22 is an opening existing in the vicinity of therotation shaft on the rotor disk 20, it works as a part for securing thesteam supply route passing the steam flow through the axial direction.Regarding the radial flow steam turbine 100 of the present invention,the steam should be introduced from the steam supply source (it is notshown in figure) up to the operating steam flow passages in which thesteam travels in the outflow direction along the radial (in aperpendicular direction relative to the rotation shaft) formed betweenthe rotor disk 20 and the stator disk 30. The through opening 22 in thevicinity of the rotation shaft works as a part of the steam supplyroute. As shown above, the steam flows along the axial direction via thethrough opening 22 on the rotor disk 20, so even if the sets of rotordisk 20 and stator disk 30 are added to the rotation shaft 10,sufficient amount of operating steam can be supplied to every turbineunit and high output can be obtained. Details of the steam flow aredescribed later on.

The shape and structure of the through opening 22 are not limited, twopatterns are described below.

FIG. 2 is a concept figure showing an example of the rotor disk 20 a andthe through opening 22 a. FIG. 2 shows a part of the rotor disk androtor blades for two stages. In FIG. 2, the rotor disk 20 a is adoughnut-shape hollow circular disk having a large center hole largerthan the diameter of the rotation shaft 10, and the rotor disk 20 a issupported by plural rotor disk supporters 11. The through opening 22 ais formed in the vicinity of the rotor axial shaft on the rotor disk 20a. The through opening 22 a shown in FIG. 2 is an inter-gap passagebetween the rotor disk supporters 11. The steam flow passes through therotor disk 20 a in the axial direction via the through opening 22 a. Thepillars shown in FIG. 2 are straight pillars and the shape of thethrough opening 22 a is a roughly quadrilateral shape, but the shape ofthe through opening 22 a can be modified appropriately according to thecondition such as the steam supply condition.

FIG. 3 is a concept figure showing another example of the rotor disk 20b and the through opening 22 b. FIG. 3 shows a part of the rotor diskand rotor blades for two stages. In FIG. 3, the rotor disk 20 b is acircular disk installed directly on the rotor axial shaft 10. Thethrough opening 22 b is formed as a through hole on the rotor disk 20 bin the vicinity of the rotation shaft 10. Steam can pass through therotor disk 20 b in the axial direction via the through opening 22 b. Thethrough opening 22 b shown in FIG. 3 is an oval shape. However, theshape of the through opening 22 b can be modified appropriatelyaccording to the condition such as the steam supply condition.

Next, the stator disk 30 is described below.

The stator disk 30 is fixed to the casing 40. The stator disk 30 isextended from the casing 40 for facing the rotor disk 20. In theconfiguration shown in FIG. 1, five stator disks 30 and four rotor disks20 are arrayed alternately. The stator disk 30 is extended from thecasing and the gap between the edge of the stator disk 30 and therotation shaft 10 is formed. This gap works as a part of the steampassage portion 32 as described later.

The stator blades 31 are mounted on the stator disk 30. The statorblades 31 are mounted corresponding to each rotor blade 21 for assistingthe rotor blades 21 to catch the force given by the operating steamflowing from the center portion to the outer radial direction. Thestator blades 31 are arrayed from the center portion to the peripheralportion along to the radial direction. These stator blades 31 on thestator disk 30 and these rotor blades 21 on the rotor disk 20 are facingeach other alternately in the radial direction. The stator disk 30 doesnot rotate because it is fixed to the casing 40.

The stator blades 31 can be mounted on either a single surface or bothsurfaces of the stator disk 30. In the configuration shown in FIG. 1,regarding the stator disk 30 fixed on the right end and the left end,the stator blades 31 are mounted on only the inside surface, andregarding the stator disk 30 in the middle, the stator blades 31 aremounted on both sides. The installation position of the stator blades 31on the stator disk 30 is on the outer part of the steam passage portion32 because the steam passage portion 32 exists in the vicinity of therotation shaft.

The number of the stator blade 31 is not limited, in this configuration,one stage of the stator blades comprises the plural stator bladesarrayed in annularly on the stator disk 30, and the multi-stage statorblades comprise plural stages mounted on the stator disk 30 arrayedannularly on concentric paths. The configuration shown in FIG. 1 is themulti-stage stator blades comprising four stages corresponding to thefour multi-stage rotor blades. The example configuration using thesingle stage stator blades 31 is described in Embodiment 2 later on.

The steam passage portion 32 is a through opening existing in thevicinity of the rotation shaft on the stator disk 30, and it works as apart of the steam supply route passing the steam flow in the axialdirection. In this configuration, the stator disk 30 is fixed to thecasing by securing the gap between stator disk edge and the rotationshaft, the gap between the edge of the stator disk 30 and the rotationshaft 10 forms the steam passage portion 32. The steam passage portion32 works as a part of the steam supply route.

Next, the casing 40 is described. The casing 40 is not limitedespecially. It is supplied as the housing for the rotation shaft 10, thebearing (not shown in figures), the rotor disk 20, and the stator disk30. The casing 40 is supported by a stand (not shown in figures). Asinner casing and an outer casing may be included in the casing 40.

It is preferable that the casing 40 is sealed appropriately for blockingthe steam leakage. The steam leakage countermeasures is important, sothe steam leakage mitigation system such as fins, shrouds or labyrinths42 is appropriately installed to the portions such as the gap betweenthe rotor disk 20 and the stator blades 31, the gap between the statordisk 30 and the rotor blades 21, the gap between the rotation shaft 10and the casing 40, and the surrounding area of the steam input opening41.

There are the steam input openings 41 in the casing 40. The steam issupplied from the steam supply source (it is not shown in figures) tothe inside of the casing 40 via the steam input openings 41. The steaminput openings 41 may be formed on one side of the casing 40 and thesteam supplied from the one side only, and the steam input openings 41may be formed on both sides of the casing 40 and the steam supplied fromboth sides.

Next, the operating steam flow passage portion 50 is described.

The operating steam flow passage portion 50 is an operating steampassage formed between facing the rotor disk 20 and the stator disk 30.The flow direction of the operating steam flow is the radial directionfrom the center portion to the outer portion. The operating steam flowpassage portion 50 passes the supplied steam from the steam supplysource (it is not shown in figures) and makes the rotor disk 20 and therotation shaft rotate.

In the configuration shown in FIG. 1, both the rotor disk 20 and thestator disk 30 are installed to the rotation shaft 10 perpendicularly,so these are facing each other in parallel, and the width of theoperating steam flow passage portion 50 is constant in the radialdirection. Other configurations are possible. Either the rotor disk 20or the stator disk 30, or both of them can have a skew against therotation shaft in order to modify the operating steam flow passageportion 50 as follows; the more the steam flows to the outer side, thelarger the width of the operating steam flow passage portion 50 becomes.As described later, the operating steam flowing in the radial directionfrom center portion outward through the operating steam flow passageportion 50 becomes high speed by expansion and running through thestator blades 31 and the rotor blades 21, so the larger the width of theoperating steam flow passage portion 50 becomes, the more the operatingsteam flows to the outer side in the radial direction.

The radial flow steam turbine 100 of the present invention may employplural steam flow passages 50. The radial flow steam turbine 100 of thepresent invention includes at least one rotor disk, rotor blades mountedon both side surfaces of the rotor disk respectively, the stator disksinstalled corresponding to both sides of each rotor disk respectively,so that at least two operating steam flow passage portions are formed.In the configuration shown in FIG. 1, there are four rotor disks 20,five stator disks 30, and eight operating steam flow passage portions50.

Next, the operating steam pressure adjusting holes 51 is described.

In the configuration shown in FIG. 1, there are four rotor disks 20,five stator disks 30, and eight operating steam flow passage portions50. In this configuration, there is no air pressure difference among thesteam flow passages 50 because there are steam supply routes in thevicinity of the rotation shaft on each rotor disks 20 respectivelythrough the axis direction. However, when the number of the stages ofthe operating steam flow passage portions 50 become larges, uneven steamexpansion may occur in the stages according to the condition such as theamount of the steam volume supplied from the steam supply source beingunstable. If the operating steam volume becomes large quickly by therapid expansion of the supplied steam, not all the supplied steam passesthrough the gap between the rotor blades 21 and the stator blades 31smoothly. In this case, the steam flow to the outflow direction isblocked and the steam flow decelerates. As shown above, the air pressuredifference occurs among the steam flow passages portions 50, whichdeteriorates the safe operation.

In this configuration, the operating steam pressure adjusting holes 51are formed on the rotor disk 20 and the stator disk 30 appropriately inorder to adjust the air pressure difference among the steam flowpassages portions 50 by connecting these steam flow passages portions 50in addition to the steam supply route. When the air pressure differenceoccurs among the steam flow passages portions 50, the steam pressure canbe adjusted among the steam flow passages portions 50 via the operatingsteam pressure adjusting holes 51. Therefore the radial flow steamturbine 100 can ease the rapid increase or decrease of the steam flowvolume appropriately, and the steam stuffing problem can be avoided.

Next, the steam flow is described.

FIG. 4 is a figure showing the steam flow superimposed onto theconfiguration shown in the FIG. 1.

The steam generated in the steam supply source (it is not shown infigures) is introduced from the steam flow input openings 41. In thisconfiguration, the steam flow input openings 41 are formed on both sidesof the casing 40, the steam is supplied from both sides into the casing40.

The introduced steam goes to the rotor disk 20 along to the rotationshaft 10, then the steam goes through the through opening 22 on therotor disk 20, and passes through the steam supply route formed by thesteam passage portion 31 on the stator disk 30. Then the steam flows inthe axial direction in the vicinity of the rotor disk 10 along to therotation shaft 10. The steam flowing in the steam supply route flows inthe axis direction, then reaches each operating steam flow passageportion 50 and bend and flows into each operating steam flow passageportion 50.

The operating steam flowing into each operating steam flow passageportion 50 in the outflow radial direction expands and runs through eachstator blade 31 and each rotor blade 21 at high speed. The steam givesthe rotation energy to each rotor blade 21, and the rotor blades 20 andthe rotation shaft 10 rotate together. In this configuration, the steamgoes through both side surfaces of the rotor disk 20, the steam passesthrough each stage of the stator blades 31 and the rotor blades 21according to the air pressure difference along the radial direction, andthe steam gives the rotation energy to each rotor blade 21 while passingthrough the operating steam flow passage portion 50.

In this configuration, the rotor blades 21 are mounted on both sidesurfaces of the rotor disk 20 and the operating steam flow passageportions 50 are formed on both side surface of the rotor disk 20. Thus,about twice the rotation torque can be obtained compared with the caseof the configuration in which the rotor blades 21 are mounted on singleside surface.

In the conventional radial flow steam turbine shown in FIG. 7, thecorresponding operating steam flow passage portion running through thestages of the stator blades and the rotor blades can be formed as onlyone, so the utilized operating steam flow passage portion is only one.On the other hand, regarding the radial flow steam turbine of thepresent invention, the configuration shown in FIG. 4 can form andutilized eight operating steam flow passage portions in the outflowdirection, and the output can be enhanced.

Embodiment 2

Embodiment 2 describes the example of the radial flow steam turbine inwhich there is a single stage of the rotor blades 21 arrayed annularlyand a single stage of the stator blades 31 arrayed annularly. The meritof the single stage is that the safe operation is possible when thesteam pressure supplied from the steam supply source is not largeenough.

FIG. 5 (a) shows the example in which two rotor disks 20 are installedon the rotation shaft 10 and three stator disks 30 are installed. Thesingle stage of the rotor blades 21 is mounted on the rotor disk 20, andthe single stage of the stator blades 31 is mounted on the stator disk30, so the unit is formed as a single stage. The number of the rotordisk 20 and the stator disk 30 can be modified corresponding to theamount of steam supplied from the steam supply source.

As shown in FIG. 5 (b), in the operation of the single stage of theradial flow steam turbine, the same as Embodiment 1, the steam generatedin the steam supply source (it is not shown in figures) is introducedfrom the steam flow input openings 41. The introduced steam goes to therotor disk 20 along to the rotation shaft 10, then the steam goesthrough the opening portion 21 on the rotor disk 20, and passes throughthe steam supply route formed by the steam passage portion 32 on thestator disk 30, then the steam flows in the axial direction in thevicinity of the rotor disk 20 along the rotation shaft 10. The steamflowing in the steam supply route flows in the axis direction, thenreaches each operating steam flow passage portion 50 and bends and flowsinto each operating steam flow passage portion 50. In thisconfiguration, the rotor blade 21 and stator blade 31 compose a singlestage, the supplied steam is not required to be high temperature andhigh pressure. If the amount of the supplied steam is large enough, therotor disk 20 and the stator disk 30 are provided in multi-stage. Thesame as Embodiment 1, a large amount of steam can be supplied enough viathe through opening 22 formed on the rotor disk 20 and the steam flowportion 32 formed on the stator disk 30.

As shown this Embodiment 2, if the steam supplied from the steam supplysource such as a boiler is not enough high temperature and highpressure, the radial flow steam turbine in which there is a single stageof the rotor blades 21 arrayed annularly and a single stage of thestator blades 31 arrayed annularly can be applied. The cost for thefacility can be restrained and the wasted heat energy from the variousindustries can be re-used.

Embodiment 3

Embodiment 3 describes the example of the radial flow steam turbine inwhich the steam flow opening 41 is formed in a single side of the casing40, and the steam is supplied from the steam supply source (it is notshown in figures) to this single side direction.

FIG. 6 is a concept figure of the radial flow steam turbine wherein thesteam is supplied from single side direction.

In the prior art, most conventional radial flow steam turbines in whichthe rotor blades are mounted onto the single side of the rotor disksupply the steam from a single direction to the single side surface ofthe rotor disk. Therefore, the thrust force along to the rotation shaftacts on the rotor disk from a single direction. For example, in order toreduce the axis direction thrust force impressed to the rotor disk, theprior art 5 employs a small hole formed on the rotor disk. However, thesteam passing through this small hole is not utilized. It is regarded asthe loss of the leaked steam.

On the other hand, the radial flow steam turbine of the presentinvention comprises the rotor blades 21 arrayed both side of the rotordisk 20, the through opening 22 in the vicinity of the rotor disk 20 forsecuring the steam supply route in the axis direction. Therefore, evenif the steam flow opening 41 is formed on the single side, the thrustforce along the rotation shaft acting on the rotor disk from a singledirection becomes very small, so the steam flowing on both sides of therotor disk can provide enough force on the rotor blades.

In the configuration shown in FIG. 6, the more the operating steam flowsto the outer direction, the larger the width of the operating steam flowpassage portion 50 becomes. Therefore the operating steam flowingthrough the operating steam flow passage portion 50 in the outflowradial direction flows and expands according to the width of theoperating steam flow passage portion 50.

FIG. 6 (b) shows a modified model of the steam supplying method forsupplying the steam to the radial flow steam turbine. The configurationshown in FIG. 6 (a) employs one steam flow opening 41 formed in thesingle side of the casing 40 as the steam supplying method for supplyingthe steam to the radial flow steam turbine. This FIG. 6 (b) also employsone steam flow opening 41 but the supplied steam is divided into theleft route and the right route for securing the two steam supply routesalong the axis direction.

As shown above, the radial flow steam turbine of the present inventionsecures the steam supply route along to the axis direction by formingthe through opening 22 in the vicinity of the rotation shaft on therotor disk 20, so the plural sets of the turbine units can be addedalong to the rotation shaft 10 easily, and the sufficient amount of thesteam can be supplied to the steam flow route along to the radialdirection. The required output can be obtained corresponding to thecondition such as the performance of the steam supply source.

While some preferable embodiments of the radial flow steam turbineaccording to the present invention are described above, it should beunderstood that various changes are possible, without deviating from thetechnical scope according to the present invention.

INDUSTRIAL APPLICABILITY

A radial flow steam turbine according to the present invention can beused as a steam turbine used for various industrial facilities becausethe turbine unit including the rotor disk and the stator disk can beadded according to the steam supply condition at the spot. For example,it can be applicable to a steam turbine for ships utilizing the wastedheat from the engine, and it can be applicable to a steam turbine forgarbage processing facilities as utilizing the wasted heat from thegarbage processing facilities.

1. A radial flow steam turbine comprising; a rotation shaft; a rotordisk connected to the rotation shaft; a rotor blade mounted on the rotordisk; a stator disk facing to the rotor disk fixed and supported by acasing; a stator blade mounted on the stator disk; wherein, the rotorblade mounted on the rotor disk and the stator blade mounted on thestator disk are arrayed alternately in the radial direction, anoperating steam flow passage in which the operating steam flows fromaround the rotation shaft in an outflow radial direction, wherein, thesteam supplied from the steam supply source flows to the operating steamflow passage as an operating steam for rotating the rotor disk and therotation shaft, an operating steam supply route along to the axialdirection is formed and secured by a through opening formed on the rotordisk in the vicinity of the rotation shaft.
 2. A radial flow steamturbine according to claim 1, wherein the number of the rotor disk is atleast one, a plurality of the rotor blades are mounted on both sides ofeach rotor disk respectively, the stator disks face both sides of eachrotor disk respectively, at least two of the operating steam flowpassages are formed, and the steam is led from the steam supply sourceto each operating steam flow passage via the steam supply route.
 3. Aradial flow steam turbine according to claim 1, wherein the rotor diskis installed on the rotation shaft directly, and the through opening ofthe rotor disk is a through hole in the vicinity of the rotation shaftof the rotor disk.
 4. A radial flow steam turbine according to claim 1,wherein the rotor disk is a doughnut-shape hollow circular disk having acenter hole larger than the diameter of the rotation shaft, the rotordisk is supported by plural rotor disk supporters fixed to the rotationshaft, and the through opening of the rotor disk in the vicinity of therotation shaft of the rotor disk is an inter-gap between the rotor disksupporters.
 5. A radial flow steam turbine according to claim 1, whereinthe stator disk is fixed to the casing by securing the gap betweenstator disk edge and the rotation shaft, and the gap between the statordisk edge and the rotation shaft forms a part of the steam supply route.6. A radial flow steam turbine according to claim 1, wherein the rotorblades mounted on the rotor disk and the stator blades mounted on thestator disk are formed outside of the steam supply route.
 7. A radialflow steam turbine according to claim 1, wherein the steam supplydirections from the steam supply source to the operating steam flowpassage via the steam supply route are two directions, the one is thedirection from the one end of the rotation shaft, the other is thedirection from the other end of the rotation shaft.
 8. A radial flowsteam turbine according to claim 1, wherein operating steam pressureadjusting holes for adjusting the air pressure gap among the operatingsteam flow passages by connecting among the operating steam flowpassages are formed on the rotor disk and the stator disk besides thesteam supply route.
 9. A radial flow steam turbine according to claim 1,wherein multi-stage rotor blades are mounted on the rotor disk arrayedalong the radial direction, wherein a single-stage of the rotor bladesis formed by mounting the rotor blades arrayed annularly on concentricpaths.